240 American Seashells 



Nassarius mendicus Gould Western Lean Nassa 



Figure 53d 



Alaska to Lower California. 



% to % inch in length, with a moderately high spire. Outer lip not 

 thickened. Sculpture consists of numerous, small beads which are formed by 

 the crossing of about a dozen small axial ribs and smaller spiral threads. Color 

 yellowish gray. Common in shallow water in the north. 



The subspecies or form cooperi Forbes has weaker spiral threads and 

 about 7 to 9 strong, whitish, smoother axial ribs which persist to the last of 

 the body whorl. Color grayish yellow to whitish, often with fine, spiral, 

 brown or mauve lines. Very common in the south. 



Subgenus Zaphon H. and A. Adams 1853 

 Nassarius fossatus Gould ^ Giant Western Nassa 



Plate 20s 



Vancouver Island to Lower California. 



I V2 to 2 inches in length, orange-brown to brownish white in color. 

 Early whorls coarsely beaded; last whorl with about a dozen coarse, variously 

 sized, flat-topped spiral threads and with about a dozen short axial ribs on the 

 top third of the last whorl. Outer lip with a jagged edge and constricted 

 at the top. The largest and one of the common intertidal Nassa snails on the 

 Pacific coast. 



Subgenus llyanassa Stimpson 1865 

 Nassarius obsoletus Say Eastern Mud Nassa 



Plate 23P 



Gulf of St. Lawrence to northeast Florida. Introduced to the Pacific 

 coast. 



/4 to I inch in length, usually covered with mud and algae, and has its 

 spire eroded at the tip. Color dark black-brown. Sculpture of numerous 

 rows of weak beads. Parietal wall thickly glazed with brown and gray. 

 Columella with a single, strong spiral ridge near the base. Outer lip with half 

 a dozen small grayish teeth which run back into the aperture. Very common 

 on oozy, warm mud flats. 



Family FASCIOLARllDAE 

 Subfamily FASCIOLARIINAE 

 Genus Leucozonia Gray 1847 



Leucozonia nassa Gmelin Chestnut Latirus 



Plate 1 1 1! 



Florida to Texas and the West Indies. 



